1. Field of the Invention
The present invention relates to an apparatus and method for controlling transmission parameters in a communication system. More particularly, the present invention relates to an apparatus and method for controlling uplink transmission power in a communication system.
2. Description of the Related Art
A communication system generally controls downlink and uplink transmission power in consideration of system capacity and service quality. Uplink transmission power control schemes are largely classified into Open Loop Power Control (OLPC) and Closed Loop Power Control (CLPC). In general, CLPC is used to compensate for short-term fading, whereas OLPC is used to compensate for parameters other than short-term fading, for example, large scale parameters such as path loss, shadowing, etc.
The following uplink transmission power control operations are performed in conventional communication systems.
A Code Division Multiple Access (CDMA) communication system controls uplink transmission power using both OLPC and CLPC.
An Orthogonal Frequency Division Multiple Access (OFDMA) communication system controls uplink transmission power using one of OLPC and CLPC. More specifically, for a Mobile Station (MS), an uplink transmission power control operation is performed using CLPC and then OLPC, or using OLPC and then CLPC.
As described above, the existing communication systems use OLPC, CLPC, or both in controlling uplink transmission power. However, they do not differentiate between the uplink transmission power used for different channels.